The Caltrops conspired to kill both Ulf and Hugh Hammer. Lord Unwin Peake had warrants for their executions drawn up, which were signed by Prince Daeron Targaryen.[1] The day that the Caltrops planned to strike, the Second Battle of Tumbleton took place. Ulf survived the battle, sleeping through every attempt to wake him. When he learned that Hugh Hammer had died during the battle, Ulf informed Lord Peake that he was going to claim the throne.[1]

The next day, Ser Hobert Hightower brought Ulf two casks of wine, one Dornish red and one Arbor gold. As Ulf preferred the sweeter vintage, the Arbor gold had been poisoned. Suspicious of Hobert's behavior, Ulf commanded the Dornish red to be set aside, and only dared drink from the poisoned Arbor gold after he had seen Hobert drink from it himself. After Hobert asked for a second cup, Ulf drank three cups himself, and soon fell asleep due to the poison.[1]

Quotes about Ulf

Ser Ulf gave himself entirely over to drunkenness, drowning himself in wine and flesh. Those who failed to please were fed to his dragon.[1]